450 Lumens Cree XML T6 Single Mode 3-18v Spare Bulb for Ultrafire Surefire 501b 502b and Hugsby Flashlight Torch Etc

It's a three star because you do have to trim a lot of the larger spring coil before it works. Yes, you will become uncomfortable with how much you're trimming. However, just keep taking it down, little piece by little piece until it begins to activate without any blinks.